Are you looking for a practical stopper for your experiment? Do you want to have a reliable test tube plug? If your answer is yes, please take at this product. This test tube stopper is made from premium rubber material, has the , meet your experiment sealing needs. Features -Color:black. -Material:Rubber -Size:2.50X2.50X2.30cm/0.98X0.98X0.90in -Size:1.70X1.70X2.30cm/0.67X0.67X0.90in -Hole diameter: 0.50cm/0.20inch. -These rubber stoppers with hole are suitable for test tubes, flasks and other laboratory equipment that need to be sealed. -Easy to take, test tube plugs are widely applied in laboratories, research institutes, universities and other places. -Taper design for easy insertion and removal, the test tube stoppers can offer you convenience. -Rubber stoppers are suitable for almost all general laboratory uses, you can use it with confidence. -Fine workmanship with premium rubber material, and good durability, the sealing plugs can be used for a long term. Package list: 10 Tubes Stoppers